In 1990s, nicotine replacement therapy is widely promoted in the world by World Health Organization to help the people to overcome the dependency on cigarette in physiology and mental, so as to give up smoking. It has been proved in clinic that nicotine is a promising and efficient drug for treating Alzheimer's disease, Parkinson's syndrome and depression. Racemic nicotine has an essentially similar pharmacological effect to natural (levogyric) nicotine, except that it is a little poor in the potential and action period relative to levogyric nicotine, but it has a much lower toxicity than that of levogyric nicotine.
Currently, the commercially available levogyric nicotine is mainly from the extract of plant, thus its use is influenced by various factors such as raw material, climate, period, etc. but racetic nicotine can be obtained only by synthesizing.
It is reported in Journal of Organic Chemistry, 1990, 55(6), 1736-44 that racemic nicotine may be synthesized from pyrrolidine by a four-step reaction, which is shown in the following reaction scheme 1.

The tert-butyl lithium and the low temperature of −120° C. in the reaction involved in this document increase the difficulty of industrial production and this method has a lower yield.
Another method reported in Journal of the Chemical Society, Perkin Transactions I, 2002(2), 143-154 prepares racemic nicotine from nicotinic acid by a four-step reaction, which is shown in the following reaction scheme 2.

Grignard reagent used in this document also restricts the use of the method in industry.
Later, it was reported in Synlett, 2009(15), 2497-2499 that racemic nicotine may be prepared from 3-pyridylaldehyde as a raw material, which is shown in the following reaction scheme 3.

Similarly as above, this method still can not substantially eliminate the problem that racemic nicotine is difficult to be produced in industry.
A method for preparing racemic nicotine reported in Journal of Heterocyclic Chemistry, 2009, 46(6), 1252-1258, is shown in the following reaction scheme 4.

It is also impossible to produce racemic nicotine in large scale, since butyl lithium is used to perform a metal exchange reaction with 3-bromopyridine at low temperature.
In sum, the current methods for preparing racemic nicotine are difficult to be used in industry production, since they not only use expensive reagents, but also are generally performed at low temperature with multiple steps and longer reaction period, and the separation and purification in each step are complicated, increasing the production cost.